Broken piece of metal in Palisades reactor should have no impact on vessel, NRC says

COVERT TOWNSHIP, MI – A broken piece of metal from an impeller blade should have no impact
on the reactor vessel or fuel at Palisades Nuclear Power Plant, the Nuclear
Regulatory Commission reported Monday.

During the outage, workers discovered that the 5 inch-by-12 inch piece of metal had
lodged inside the vessel, but were unable to remove it, the
Kalamazoo Gazette reported earlier this month. The metal was located between the
vessel wall and the fuel skirt and was separated from the fuel, a spokeswoman for Entergy Corp., which owns Palisades, said at the time. It
was one of two issues that came to light during the Palisades outage that were
the subject of NRC reviews before the plant started up on Sunday.

"The NRC conducted an in-depth, independent review of the plant
analysis of the impact the piece of metal within the vessel may have on the reactor
vessel and fuel safety. The licensee's evaluation and analysis provided the NRC
with sufficient basis to conclude that the impeller piece will not impact the
reactor vessel or the fuel within the vessel," according to the result of the review reported Monday. "The piece is not likely to impede
flow to the fuel during normal operation or an accident."

In the "unlikely event" of an impact, the plant's instrumentation
should alert workers to the existence of foreign material within the fuel
plenum, the review said.

"In addition, plant operators are trained and are aware of
immediate actions necessary to mitigate the event before it poses a significant
safety concern either to the plant or to the public," the review said. "The agency
concluded that the plant can continue to operate safely."

The second issue had to do with flaws found in 17 of the control rod drive mechanism housings. In January, a spokeswoman for Palisades said it would replace
all 17, as well as several others that "did not meet its criteria." Ultimately, the nuclear power plant replaced 44 of the 45 with a different
design, according to the NRC review. The 45th had already been replaced during a previous
outage.

The housings, which are part of the reactor coolant system
pressure boundary, are meant to prevent coolant from leaking into the
containment.

Two NRC resident inspectors and an NRC regional inspector observed
the examination and the corrective actions, the report said. In addition to the
onsite observation, NRC headquarters and regional experts conducted an
independent review of the technical evaluations and the destructive testing of four
of the flawed housings.

"Based upon its independent review and assessment, the NRC
concluded that the CRDM housings' structural integrity was not compromised
while the plant was operating," the review said.

Yvonne Zipp is a staff writer at the Kalamazoo Gazette. Email her at yzipp@mlive.com or follow her on Twitter.